Smart multiplexed medical laser system

ABSTRACT

A system includes a laser catheter and a rotating optical member to receive a laser beam along an optical path and rotate to a selected position to redirect the laser beam from the optical path onto one or more selected optical fibers of a laser catheter, wherein a distal end of the laser catheter irradiates an endovascular structure.

FIELD

The disclosure relates generally to endovascular devices and particularly to laser catheters.

BACKGROUND

Laser energy can be transmitted through multiple optical fibers housed in a relatively flexible tubular catheter inserted into a body lumen, such as a blood vessel, ureter, fallopian tube, cerebral artery and the like to remove obstructions in the lumen. Catheters used for laser angioplasty and other procedures can have a central passage or tube which receives a guide wire inserted into the body lumen (e.g., vascular system) prior to catheter introduction. The guide wire facilitates the advancement and placement of the catheter to the selected portion(s) of the body lumen for laser ablation of tissue.

In designing a laser catheter, there are a number of considerations.

For example, laser energy should be controllably and selectively delivered onto single fibers or smaller sub-bundles of subsets of fibers that make up the total number of fibers that are incorporated into the device. This can reduce the overall impact of heat or acoustic shock that can damage tissue adjacent to the treatment site by dividing the transmitted laser energy into smaller packets. It can enable selective treating and targeting of specific zones encountered by the distal tip of the catheter by activating only the fibers required to heat those zones. It can reduce the overall power and energy requirements of the treatment laser by activating smaller portions of fibers in the catheter rather than activating all of the fibers simultaneously. When the instantaneous energy delivered by laser angioplasty catheters is maintained below an “adverse effect” threshold, while at the same time delivering the proper fluence values for tissue ablation, a significant reduction in the incidence of undesirable tissue damage can occur. Previous laser catheters able to energize controllably and selectively fibers used fairly complex scan systems including galvanometer scanners (open and closed loop), piezo type deflection devices, and other mechanical beam or coupler deflection systems. These types of systems typically require a fairly complex and expensive drive and control system. Often, diseased tissue is present in locations where only a portion of the laser catheter's distal tip is in contact with the diseased tissue. It may be desirable to activate only the portion of the distal tip in contact with the diseased tissue. Additionally, laser catheters are used to cut or ablate adhesions holding implanted objects in biological tissue. For safety reasons, it may be desirable to ablate only the tissue in contact with the laser delivery device tip and to avoid ablating tissue adjacent to the wall or artery to prevent perforation.

Notwithstanding these considerations, laser catheters typically energize all of the fibers simultaneously to achieve bulk ablation. Such fiber activation outputs energy from all fibers simultaneously. The resultant instantaneous energy required to achieve the fluence, or energy density values for ablation, can become high enough to induce undesirable tissue damage, including laser induced dissection.

SUMMARY

These and other needs are addressed by the various aspects, embodiments, and/or configurations of the present disclosure. A method in accordance with this disclosure can include the steps:

(a) directing a laser beam along an optical path onto a rotating optical member and

(b) rotating the optical member to redirect the laser beam from the optical path onto one or more selected optical fibers of a laser catheter; and

(c) irradiating, by a distal end of the laser catheter, an endovascular structure.

A system in accordance with this disclosure can include:

(a) a laser catheter and

(b) a rotating optical member to receive a laser beam along an optical path and rotate to a selected position to redirect the laser beam from the optical path onto one or more selected optical fibers of a laser catheter, wherein a distal end of the laser catheter irradiates an endovascular structure.

A tangible, non-transient computer readable medium, in accordance with this disclosure, can include microprocessor executable instructions that, when executed, perform operations comprising:

(a) directing a laser beam along an optical path onto a rotating optical member; and

(b) rotating the optical member to redirect the laser beam from the optical path onto one or more selected optical fibers of a laser catheter; and

(c) irradiating, by a distal end of the laser catheter, an endovascular structure.

The rotating optical member can be one or more of a wedge prism, a faceted optic, an axicon, and a parallel faced optic.

When the rotating optical member is a parallel faced optic and the laser beam is incident upon a face of the parallel faced optic, the incident face can be nonorthogonal to the optical path of the laser beam.

The disclosure can include a detector and/or proximity sensor to sense:

at a first time, a first position of the rotating optical member, wherein at the first position the redirected laser beam irradiates a first, but not a second, set of optical fibers; and

at a second time, a second position of the rotating optical member, wherein at the second position the redirected laser beam irradiates the second, but not the first, set of optical fibers.

The disclosure can include a microprocessor executable controller operable to select, based on one or more of total fiber active area of the laser catheter, imaging information regarding the target and/or non-target endovascular structure(s), target endovascular structure characterization information, and current location and/or orientation of a distal tip of the laser catheter, at least one of a fiber active area for each optical channel, a number of optical channels, a configuration of fibers in an optical channel, an optical channel to be irradiated, and an ordering of optical channel irradiation.

The redirected laser beam can irradiate plural optical fibers positioned along an arc defined by the laser beam during rotation of the optical member.

The present disclosure can provide a number of advantages depending on the particular aspect, embodiment, and/or configuration. Laser energy can be controllably and selectively delivered onto single fibers or smaller sub-bundles of subsets of fibers that make up the total number of fibers that are incorporated into the device. This can reduce the overall impact of heat or acoustic shock that can damage tissue adjacent to the treatment site by dividing the transmitted laser energy into smaller packets. It can enable selective treating and targeting of specific zones encountered by the distal tip of the catheter by activating only the fibers required to heat those zones. It can reduce the overall power and energy requirements of the treatment laser by activating smaller portions of fibers in the catheter rather than activating all of the fibers simultaneously. Activating portions of the distal tip of the catheter using the treatment laser or other diagnostic light source to probe the area of the lesion contact or tissue disease type and/or location to assess the best method or location of the fibers to be activated at the distal end for treatment. This can be accomplished using a simpler and relatively inexpensive beam deflection mechanism. By using rotating optics and rotational position monitoring using encoders or proximity sensors to fire the laser at the exact time the beam is incident on the target fiber or bundles of fibers, a much simpler multiplexed system can be provided. It can eliminate costly galvanometer scanners and amplifiers with closed loop position feedback electronics. A circular multi-fiber coupler can be fabricated easily. Controllable and selective fiber energizing can enable activating only the portion of the distal tip in contact with the diseased tissue. Additionally, it can ablate only the tissue in contact with the laser delivery device tip and avoid ablating tissue adjacent to the wall or artery to prevent perforation. It can avoid providing too much instantaneous energy and inducing undesirable tissue damage, including laser induced dissection. In other words, it can maintain the instantaneous energy delivered by laser angioplasty catheters below the “adverse effect” threshold, while at the same time delivering the proper fluence values for tissue ablation, thereby providing a significant reduction in the incidence of undesirable tissue damage should occur.

These and other advantages will be apparent from the disclosure.

The phrases “at least one”, “one or more”, and “and/or” are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B and C”, “at least one of A, B, or C”, “one or more of A, B, and C”, “one or more of A, B, or C” and “A, B, and/or C” means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together.

The term “a” or “an” entity refers to one or more of that entity. As such, the terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein. It is also to be noted that the terms “comprising”, “including”, and “having” can be used interchangeably.

The term “automatic” and variations thereof, as used herein, refers to any process or operation done without material human input when the process or operation is performed. However, a process or operation can be automatic, even though performance of the process or operation uses material or immaterial human input, if the input is received before performance of the process or operation. Human input is deemed to be material if such input influences how the process or operation will be performed. Human input that consents to the performance of the process or operation is not deemed to be “material”.

An “axicon” is an optical element that produces a line image lying along the axis from a point source of light; therefore, it has no definite focal length. An example is a lens with a weak conical surface on one face.

The term “computer-readable medium” as used herein refers to any storage and/or transmission medium that participate in providing instructions to a processor for execution. Such a medium is commonly tangible and non-transient and can take many forms, including but not limited to, non-volatile media, volatile media, and transmission media and includes without limitation random access memory (“RAM”), read only memory (“ROM”), and the like. Non-volatile media includes, for example, NVRAM, or magnetic or optical disks. Volatile media includes dynamic memory, such as main memory. Common forms of computer-readable media include, for example, a floppy disk (including without limitation a Bernoulli cartridge, ZIP drive, and JAZ drive), a flexible disk, hard disk, magnetic tape or cassettes, or any other magnetic medium, magneto-optical medium, a digital video disk (such as CD-ROM), any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, a RAM, a PROM, and EPROM, a FLASH-EPROM, a solid state medium like a memory card, any other memory chip or cartridge, a carrier wave as described hereinafter, or any other medium from which a computer can read. A digital file attachment to e-mail or other self-contained information archive or set of archives is considered a distribution medium equivalent to a tangible storage medium. When the computer-readable media is configured as a database, it is to be understood that the database may be any type of database, such as relational, hierarchical, object-oriented, and/or the like. Accordingly, the disclosure is considered to include a tangible storage medium or distribution medium and prior art-recognized equivalents and successor media, in which the software implementations of the present disclosure are stored. Computer-readable storage medium commonly excludes transient storage media, particularly electrical, magnetic, electromagnetic, optical, magneto-optical signals.

The terms “determine”, “calculate” and “compute,” and variations thereof, as used herein, are used interchangeably and include any type of methodology, process, mathematical operation or technique.

A “laser emitter” refers to an end portion of a fiber or an optical component that emits laser light from a distal end of the catheter towards a desired target, which is typically tissue.

A “catheter” is a tube that can be inserted into a body cavity, duct, lumen, or vessel, such as the vasculature system. In most uses, a catheter is a thin, flexible tube (“soft” catheter), though in some uses, it may be a larger, solid less flexible—but possibly still flexible—catheter (“hard” catheter).

“Coronary catheterization” is a generally minimally invasive procedure to access the coronary circulation and/or blood filled chambers of the heart using a catheter. It is performed for both diagnostic and interventional (treatment) purposes.

A “coupler” or “fiber optic coupler” refers to the optical fiber device with one or more input fibers and one or several output fibers. Fiber couplers are commonly special optical fiber devices with one or more input fibers for distributing optical signals into two or more output fibers. Optical energy is passively split into multiple output signals (fibers), each containing light with properties identical to the original except for reduced amplitude. Fiber couplers have input and output configurations defined as M×N. M is the number of input ports (one or more). N is the number of output ports and is always equal to or greater than M. Fibers can be thermally tapered and fused so that their cores come into intimate contact. This can also be done with polarization-maintaining fibers, leading to polarization-maintaining couplers (PM couplers) or splitters. Some couplers use side-polished fibers, providing access to the fiber core. Couplers can also be made from bulk optics, for example in the form of microlenses and beam splitters, which can be coupled to fibers (“fiber pig-tailed”).

“Electromagnetic radiation” or “EM radiation” or “EMR” is a form of energy emitted and absorbed by charged particles which exhibits wave-like behavior as it travels through space. EMR has both electric and magnetic field components, which stand in a fixed ratio of intensity to each other, and which oscillate in phase perpendicular to each other and perpendicular to the direction of energy and wave propagation. The electromagnetic spectrum, in order of increasing frequency and decreasing wavelength, consists of radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays and gamma rays.

A “lead” is a conductive structure, typically an electrically insulated coiled wire. The electrically conductive material can be any conductive material, with metals and intermetallic alloys common. The outer sheath of insulative material is biocompatible and biostable (e.g., non-dissolving in the body) and generally includes organic materials such as polyurethane and polyimide. Lead types include, by way of non-limiting example, epicardial and endocardial leads. Leads are commonly implanted into a body percutaneously or surgically.

The term “means” as used herein shall be given its broadest possible interpretation in accordance with 35 U.S.C., Section 112, Paragraph 6. Accordingly, a claim incorporating the term “means” shall cover all structures, materials, or acts set forth herein, and all of the equivalents thereof. Further, the structures, materials or acts and the equivalents thereof shall include all those described in the summary of the invention, brief description of the drawings, detailed description, abstract, and claims themselves.

The term “module” as used herein refers to any known or later developed hardware, software, firmware, artificial intelligence, fuzzy logic, or combination of hardware and software that is capable of performing the functionality associated with that element. Also, while the disclosure is presented in terms of exemplary embodiments, it should be appreciated that individual aspects of the disclosure can be separately claimed.

An “optical fiber” or “laser active fiber” is a flexible, transparent fiber made of an optically transmissive material, such as glass (silica) or plastic that functions as a waveguide, or “light pipe”, to transmit light between the two ends of the fiber.

A “surgical implant” is a medical device manufactured to replace a missing biological structure, support, stimulate, or treat a damaged biological structure, or enhance, stimulate, or treat an existing biological structure. Medical implants are man-made devices, in contrast to a transplant, which is a transplanted biomedical tissue. In some cases implants contain electronics, including, without limitation, artificial pacemaker, defibrillator, electrodes, and cochlear implants. Some implants are bioactive, including, without limitation, subcutaneous drug delivery devices in the form of implantable pills or drug-eluting stents.

The preceding is a simplified summary of the disclosure to provide an understanding of some aspects of the disclosure. This summary is neither an extensive nor exhaustive overview of the disclosure and its various aspects, embodiments, and/or configurations. It is intended neither to identify key or critical elements of the disclosure nor to delineate the scope of the disclosure but to present selected concepts of the disclosure in a simplified form as an introduction to the more detailed description presented below. As will be appreciated, other aspects, embodiments, and/or configurations of the disclosure are possible utilizing, alone or in combination, one or more of the features set forth above or described in detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a distal tip of a laser catheter containing a lumen;

FIG. 2 depicts a distal tip of a lumenless laser catheter;

FIG. 3 is a cross-sectional view of the distal tip of FIG. 1 approaching target tissue or other endovascular structure;

FIG. 4 is a block diagram of a multiplexed laser catheter according to an embodiment;

FIG. 5 is a block diagram of a multiplexed laser catheter according to an embodiment;

FIG. 6 is a block diagram of a control system according to an embodiment;

FIGS. 7A-B depict a fiber array according to an embodiment;

FIG. 8 depicts a multiplexing system according to an embodiment;

FIGS. 9A-C depict a fiber array according to an embodiment;

FIG. 10 depicts a control algorithm according to an embodiment; and

FIG. 11 depicts a first energizing mode;

FIGS. 12A-B depict a second energizing mode;

FIGS. 13A-C depict a third energizing mode; and

FIGS. 14A-D depict a fourth energizing mode.

DETAILED DESCRIPTION

FIGS. 1 and 2 depict the working or distal ends of various known prior art laser catheters having plural optical fibers 324 embedded therein. FIG. 1 shows a flexible catheter 100 comprising a catheter lumen 104 to receive an implanted lead or guide wire (not shown) and plural laser emitters 108 positioned around the periphery or diameter of the catheter lumen 104. This type of catheter assembly is sold as a coronary laser atherectomy catheter by the Spectranetics Corporation under the tradenames ELCA™ and Turbo Elite™ (each of which is used for coronary intervention or catheterization such as recanalizing occluded arteries, changing lesion morphology, and facilitating stent placement) and as a laser sheath under the tradename SLSII™ and GlideLight™ (which is used for surgically implanted lead removal). FIG. 2 shows a flexible catheter 200 comprising plural laser emitters 108 packed into the distal end of the catheter. The number of rows of optical fibers and emitters located in the catheter and/or located concentrically around the lumen and the number of optical fibers and emitters in each row can vary by application and are not limited to the depicted configurations. The primary difference between the catheters in FIGS. 1 and 2 is the absence of a catheter lumen 104 in the catheter of FIG. 2 .

Referring to FIG. 3 , a laser ablation catheter 300 is positioned in a body lumen 304, such as a blood vessel, to remove a complete or partial occlusion 308. A guide wire 312 passes through the body lumen 304 and occlusion 308 on the one hand and the catheter lumen 316 formed by a substantially cylindrical inner catheter surface 320 on the other to guide the catheter to the occlusion 308. Laser emitters 108 are positioned at the distal end of the catheter to ablate the occlusion. Optical fiber 324 connects a corresponding emitter to the laser via the proximal end or coupler (FIG. 8 ).

FIG. 8 depicts a laser assembly 800 including a laser 804, such as a low-temperature excimer laser operating in the ultraviolet spectrum at around 308 nm, a lens assembly 824 (which includes one or more lenses and/or filters), a fiber selector 808 to controllably and selectively energize fibers 108, a coupler 812 to couple to a proximal end of the laser catheter 300, and plural optical channels, each channel being represented by a corresponding first, second, third, . . . nth optic fiber set 818 a-n. The laser 804 emits laser energy or beam 828, which is directed by the laser assembly 800 to the fiber selector 808. The fiber selector 808 directs the laser energy 828, through the coupler 812, and onto a selected one of the first, second, third, . . . nth optic fiber set 818 a-n. As will be appreciated, the laser 804 can be the same for both treatment and diagnostic laser pulses or different lasers may be employed. When compared to treatment laser pulses, diagnostic laser pulses use lower power.

FIG. 6 depicts a control system 600 according to an embodiment. The control system 600 includes a controller 604 (which is typically a microprocessor) in signal and electrical communication with a memory 608, laser circuitry 612 to operate the laser 804, a user interface 616 to receive commands from and provide queries, target tissue or other endovascular structure information, and other feedback to a user, a target acquisition module 620 to determine target tissue or other endovascular structure location and/or characterization information, a detector 624 to select an optical channel from among plural optical channels for energization, scanner drive electronics 628 to operate the fiber selector 808 for energizing selected optical channels, and an optional catheter size information receiver 632 to receive information regarding the total fiber active area at the distal tip of the catheter. The controller 604 can use target tissue or other endovascular structure location and other imaging or diagnostic information, target tissue or other endovascular structure characterization information (such as tissue density, type, location, and configuration) and/or target tissue or other endovascular structure proximity to other non-target tissue structures, such as blood vessel walls, and total fiber active area at the distal end or tip to select not only laser parameters (such as, for each selected optical channel, fluence, energy density value, intensity, an active area, a maximum allowable fluence, a minimum allowable fluence, repetition rate (e.g., lasing on/off time), and lasing train time) but also the number of optical channels, the fiber active area for each optical channel, the fiber configuration for each optical channel, the specific optical channels to energize for target tissue ablation, and the sequence for energizing the selected channels.

The memory 608 can be any computer readable medium and stores, for a current catheterization procedure, a variety of information, including target tissue or other endovascular structure location, characterization information, target tissue or other endovascular structure proximity to non-target tissue structures and other imaging information, laser parameters, optical channel number and configuration, optical channel energizing sequence or ordering, patient information, total fiber active area of the distal end or tip, timestamps, and the like. It can also store various look up tables to enable the controller 604 to configure the optical channels for a currently connected catheter based on the total fiber active area of the catheter. Thus, different models or types or configurations of catheters having different total fiber active areas can have different numbers and configurations of optical channels.

Laser circuitry 612 enables operation of the laser by the controller 604 in response to user commands received by the user interface 616. The laser circuitry 612 is conventional.

The user interface 616 can be any audio, video, and/or tactile interface, such as a keyboard, display, microphone, and the like.

The target acquisition module 620 acquires imaging information via a target imaging (and/or diagnostic) module 636 (hereinafter referred to as target imaging module 636). The imaging information relates not only to the structure of the target tissue or other endovascular structure, such as an occlusion, unwanted tissue growth in proximity to a surgically implanted structure, and the like but also to non-target tissue structures in proximity to the target tissue structure. The target imaging module 636 can be any suitable imaging device, such as, but not limited to, laser induced fluorescence spectroscopy, optical coherence reflectometry, optical coherence tomography, and Raman spectroscopy. The imaging information can be a two, three, or four dimensional representation of the imaged tissue structures.

The detector 624 operatively engages the fiber selector 808 to determine a current optical channel positioned for energizing by the laser and/or a position of a selected optical channel relative to a desired position for the optical channel. The detector 624 can be any suitable configuration, whether a mechanical, optical, electrical, and/or electromagnetic device for tracking movement and/or a current position of the fiber selector 808. It can also be configured as one or more proximity sensors to fire the laser at the precise time that the beam is incident on the target fibers or bundles (or set) of fibers.

The scanner drive electronics 628 one or more of controllably directs the laser beam in a desired orientation and/or controls movement of the fiber selector 808. An example of the former configuration is described in U.S. Pat. No. 5,400,428 to Grace, which is incorporated herein by this reference. Grace discloses a dielectric mirror mounted on a galvanometer scanner that is moved to cause successive laser pulses to irradiate different optical channels, thereby enabling each fiber to receive radiation having sufficient fluence while reducing the energy per pulse (or the cw equivalent). Examples of the latter configuration are discussed below.

The catheter size information receiver 632 can be any configuration. For example, it can be based on a lookup table using an identifier of the catheter. The identifier can be provided by a pin sequence or configuration on the proximal end of the catheter. The sequence and/or configuration of pins is mounted to the proximal end of the catheter. The pin arrangement or sequence actuates switches in the catheter's coupler to generate a signal, which is forwarded to the controller 604. Using a lookup table in memory 608 and the signal, the controller 604 can identify the type and/or model of the catheter and therefore the appropriate catheter specifications, requirements, and other operating information. Each type and/or model of catheter has a unique pin sequence to actuate different switches for generating different signals. Other techniques for providing the identifier to the controller 604 may also be employed, such as the techniques discussed in copending U.S. patent application Ser. No. 13/804,812, filed Mar. 14, 2013, and entitled “Intelligent Catheter”, which is incorporated herein by reference in its entirety.

Various configurations of the fiber selector 808 will now be discussed with reference to FIGS. 4-5, 7A-B, and 9A-C. Although the fiber selector 808 is shown as being distal to the coupler, it may be positioned within or proximal to the coupler, depending on the application.

Referring to FIG. 4 , a first fiber selector configuration is depicted. While FIG. 4 and other figures depict the optical fibers as a linear array for purposes of simplicity, it is to be understood that other fiber arrangements can be employed, particularly fibers oriented in a three dimensional array.

The fiber selector 808 comprises a rotating wedge optical member 400 positioned in the optical path 404 of the laser beam 408 to redirect, by optical refraction, the laser beam onto one or more selected fibers 324, with the optical fiber(s) irradiated at any one time corresponding to an optical channel and optical fiber(s) irradiated at different times corresponding to different optical channels. As will be appreciated, a wedge prism can be uncoated or coated with an anti-reflection coating and can deviate an angle of an incident beam. Typically, the wedge prism deviates the angle of the laser beam by an amount ranging from about 70 to about 20 degrees. The wedge optical member 400 typically has a thickness that is dependent upon the desired beam deviation, which is a also a function of the size of the coupler. This causes the laser beam 408 to be diverted at an angle Ω 428 relative to the optical path 404 along a diverging optical path. The motor-driven rotation of the optical member can be at fixed and/or variable speeds.

Alternatively, plural wedge optical members can be used to redirect the laser beam. For example, two wedge prisms can be used as an anamorphic pair to steer the beam anywhere within a circle described by the full angle 4θ , where θ is the deviation from a single prism. This beam steering is accomplished by rotating the two wedge prisms independently of each other.

The position of the wedge optical member 400 can be determined by the detector 624 based upon, for example, radiation reflected by a locating member 432, which rotates simultaneously and in an amount related to rotation of the wedge optical member 400. For example, the locating member 432 can be encoded with encoding elements that reflect light uniquely or substantially uniquely for any position around the circumference of the locating member 432. To produce the unique light reflectance can be the result of the encoding elements being differently sized, spaced, and/or colored. An example of such encoding elements is a bar code. The detector 624 emits light onto the locating member, detects the reflected spectra, and maps the reflected spectra against a lookup table that indexes each absolute and/or relative position around the locating member 432 against a corresponding set of reflected spectra. Based on the comparison, a locating signal is generated and sent to the controller 604, which then instructs a subcontroller (not shown), which further instructs the motor (not shown) to rotate the wedge optical member 400 a selected angle to align the selected optical channel with the redirected laser beam 408. By incorporating the optical encoder, the laser can be fired at the time the beam is deflected to the position to couple into the desired fiber or bundle of fibers. While tracking the position of the wedge optical member 400 is discussed with reference to an optical encoder, other types of encoders may be employed, such as mechanical, electrical, and/or electromagnetic position tracking devices.

Referring to FIG. 5 , a second fiber selector configuration is depicted.

The fiber selector 808 comprises a rotating parallel-faced optical member 500 positioned in the optical path 404 of the laser beam 408 to redirect, by optical refraction, the laser beam onto one or more selected fibers 324. The parallel-faced optical member 500 comprises opposing parallel faces 504 and 508 and is inclined relative to the optical path 404 at an angle δ 512 sufficient to deviate the laser beam 408 from the optical path 408 by an angle ranging from about 70 to about 20 degrees. The optical member 500 typically has a thickness that is dependent upon the desired beam deviation, which is a also a function of the size of the coupler. The inclined parallel surfaces 504 and 512 cause the laser beam 408 to be diverted and offset relative to and substantially parallel to the optical path 404.

In the first and second fiber selector configurations, the direction of rotation, whether clockwise, counterclockwise or both, is a matter of design choice.

In each of the first and second fiber selector configurations, complete rotation of the optical member causes the laser beam to trace, or define, a circle on the optical fibers. Partial rotation of the optical member causes the laser beam to trace a partial circle, with the length of the arc being proportional to the degree of rotation of the optical member. Any optical fiber positioned along the arc is irradiated by the incident redirected laser beam.

Other types of optical members may be used. For example, a faceted optical member, known as an axicon, may also be employed. In another example, a faceted optical element is employed.

Referring to FIGS. 7A-B, a third fiber selector configuration is depicted. This configuration is further discussed in U.S. Pat. No. 5,400,428 referenced above.

A grooved fiber holder 700 holds two equally sized bundles of fibers 818 a,b, each bundle corresponding to a different optical channel. Bundles 818 a,b are centered upon the same linear transverse axis 704. The laser beam is focused so that the first incident beam pulse irradiates all of fiber bundle 818 b (FIG. 7A), which is half of the total fibers. Either the beam or the fibers are then shifted so that next pulse of the laser beam is focused on bundle 818 a (FIG. 7B). The grooved fiber holder 700 can be translated along the linear transverse axis 704 by displacing the holder 700 laterally in a carrier member 708, such as energizing a piezoelectric stack or a motor.

Referring to FIGS. 9A-C, a fourth fiber selector configuration is depicted. FIGS. 9A-C illustrate three bundles of optical fibers 818 a, 818 b and 818 c, each bundle corresponding to a different optical channel. Each bundle of fibers 818 a, 818 b and 818 c contains ⅓ of the total number of fibers. The optical fiber bundles are disposed in a grooved fiber holder 900 that moves laterally within a holder 904 as discussed above. First scan position (FIG. 9A) irradiates fiber bundle 818 a. In a second scan position (FIG. 9B), the beam and fibers are moved relative to one another to irradiate the second fiber bundle 818 b. In a third scan position (FIG. 9C), the next laser pulse is directed at the third bundle of optical fibers 818 c. As in FIG. 5 a , the fiber bundles are disposed in a linear manner along the same transverse axis 320 to provide for linear scanning

As will be appreciated, other fiber selector configurations may be employed.

Regardless of the fiber selector configuration employed, the distal end or tip of the catheter energizes all or part of the laser emitters 108 as shown in FIGS. 11, 12A-B, 13A-C, and 14A-D. As noted, the portion of the laser emitters 108 energized, or the number of optical channels employed, depend on one or more of target tissue or other endovascular structure location, target tissue or other endovascular structure characterization information (such as tissue density, type, location, and configuration), current location and/or orientation of the distal tip of the catheter, and/or target tissue or other endovascular structure proximity to other non-target tissue structures, and total fiber active area at the distal end or tip. In FIGS. 11, 12A-B, 13A-C, and 14A-D, darkened laser emitters refer to those being energized while undarkened laser emitters refer to those not being energized.

FIG. 11 depicts a first operating mode in which all of the laser emitters 108 in the distal tip of the catheter are energized simultaneously.

FIGS. 12A-B depict a second operating mode for a 2-way multiplexing configuration in which one-half of the laser emitters 108 are energized simultaneously at a first time and the other half of the laser emitters 108 are energized simultaneously at a second (different) time. This operating mode can be produced by any of the first, second, and third fiber selector configurations.

FIGS. 13A-C depict a third operating mode for a 3-way multiplexing configuration in which a first one-third of the laser emitters 108 is energized simultaneously at a first time, a second one-third of the laser emitters 108 is energized simultaneously at a second time, and a third one-third of the laser emitters 108 is energized simultaneously at a third time. The first, second, and third times are different. This operating mode can be produced by any of the first, second, and fourth fiber selector configurations.

FIGS. 14A-D depict a fourth operating mode for a 4-way multiplexing configuration in which a first one-quarter of the laser emitters 108 is energized simultaneously at a first time, a second one-quarter of the laser emitters 108 is energized simultaneously at a second time, a third one-quarter of the laser emitters 108 is energized simultaneously at a third time, and a fourth one-quarter of the laser emitters 108 is energized simultaneously at a fourth time. The first, second, third, and fourth times are different. This operating mode can be produced by any of the first and second fiber selector configurations.

As will be appreciated, multiplexing may be performed up to N ways, with N being a whole number. Multiplexing is not limited to 2, 3, and 4 ways as shown in the above figures.

As will be further appreciated, the geometrical pattern of laser emitters 108 energized can be different from those shown. The laser emitters 108 can be energized along an arc, be randomly distributed, and/or be uniformly or nonuniformly distributed around the circumference of the distal tip of the catheter.

An operation of the controller 604 will now be described with reference to FIG. 10 .

The operation commences in step 1000 in which the controller 604 detects a stimulus. The stimulus can be, for example, a command received from an operator, such as a physician, via the user interface 616.

The controller 604 determines a total fiber active area of the catheter currently coupled to the coupler 812.

The controller 604, in step 1008, selects a number of optical channels based on the determined total fiber active area. As noted, this can be done using a lookup table. In other configurations, the controller 604 can use other information, particularly imaging information (including target tissue or other endovascular structure location, target tissue or other endovascular structure characterization information (such as tissue density, type, location, and configuration), current location and/or orientation of the distal tip of the catheter, and/or target tissue or other endovascular structure proximity to other non-target tissue structures) received from the target acquisition module 620 in addition to or lieu of the total fiber active area in selecting the number of optical channels. In that event, step 1008 would follow step 1012.

In one application, the controller 604 selects one or more of a fiber active area for each optical channel, a number of optical channels, a configuration of fibers in an optical channel, an optical channel to be irradiated, and an ordering of optical channel irradiation based on one or more of total fiber active area of the laser catheter, imaging information regarding the target and/or non-target endovascular structure(s), target endovascular structure characterization information, and current location and/or orientation of a distal tip of the laser catheter.

In step 1012, the controller 604 receives target acquisition information from the target acquisition module 620 and indirectly from the target imaging module 636. The target acquisition information is typically imaging information. In some configurations, additional wavelengths of light are launched down the fibers and through the laser emitters in the catheter and returned or reflected light analyzed to determine reflectivity and absorption data. This can be used to determine target and/or non-target tissue or other endovascular structure location, type, and/or contact area (area of contact between the distal tip and structure of the target tissue or other endovascular structure).

In step 1016, the controller 604 selects which of the optical channels to energize to ablate the target tissue or other endovascular structure. This can be determined based upon any or all of the information referenced in the prior paragraph and/or user input.

In step 1020, the controller 604 determines an energization sequence. The sequence governs which optical channels are energized and in what order and times. This can be determined based upon any or all of the information referenced previously including imaging information and user input.

In step 1024, the controller 604 initiates optical channel energization in accordance with the determined energization sequence.

The exemplary systems and methods of this disclosure have been described in relation to a laser catheter. However, to avoid unnecessarily obscuring the present disclosure, the preceding description omits a number of known structures and devices. This omission is not to be construed as a limitation of the scopes of the claims. Specific details are set forth to provide an understanding of the present disclosure. It should however be appreciated that the present disclosure may be practiced in a variety of ways beyond the specific detail set forth herein.

Furthermore, while the exemplary aspects, embodiments, and/or configurations illustrated herein show the various components of the system collocated, certain components of the system can be located remotely, at distant portions of a distributed network, such as a LAN and/or the Internet, or within a dedicated system. Thus, it should be appreciated, that the components of the system can be combined in to one or more devices, such as a base unit, or collocated on a particular node of a distributed network.

Furthermore, it should be appreciated that the various links connecting the elements can be wired or wireless links, or any combination thereof, or any other known or later developed element(s) that is capable of supplying and/or communicating data to and from the connected elements. These wired or wireless links can also be secure links and may be capable of communicating encrypted information. Transmission media used as links, for example, can be any suitable carrier for electrical signals, including coaxial cables, copper wire and fiber optics, and may take the form of acoustic or light waves, such as those generated during radio-wave and infra-red data communications.

Also, while the flowcharts have been discussed and illustrated in relation to a particular sequence of events, it should be appreciated that changes, additions, and omissions to this sequence can occur without materially affecting the operation of the disclosed embodiments, configuration, and aspects.

A number of variations and modifications of the disclosure can be used. It would be possible to provide for some features of the disclosure without providing others.

For example, the systems and methods of this disclosure can be implemented in conjunction with a special purpose computer, a programmed microprocessor or microcontroller and peripheral integrated circuit element(s), an ASIC or other integrated circuit, a digital signal processor, a hard-wired electronic or logic circuit such as discrete element circuit, a programmable logic device or gate array such as PLD, PLA, FPGA, PAL, special purpose computer, any comparable means, or the like. In general, any device(s) or means capable of implementing the methodology illustrated herein can be used to implement the various aspects of this disclosure. Exemplary hardware that can be used for the disclosed embodiments, configurations and aspects includes computers, handheld devices, telephones (e.g., cellular, Internet enabled, digital, analog, hybrids, and others), and other hardware known in the art. Some of these devices include processors (e.g., a single or multiple microprocessors), memory, nonvolatile storage, input devices, and output devices. Furthermore, alternative software implementations including, but not limited to, distributed processing or component/object distributed processing, parallel processing, or virtual machine processing can also be constructed to implement the methods described herein.

In yet another embodiment, the disclosed methods may be readily implemented in conjunction with software using object or object-oriented software development environments that provide portable source code that can be used on a variety of computer or workstation platforms. Alternatively, the disclosed system may be implemented partially or fully in hardware using standard logic circuits or VLSI design. Whether software or hardware is used to implement the systems in accordance with this disclosure is dependent on the speed and/or efficiency requirements of the system, the particular function, and the particular software or hardware systems or microprocessor or microcomputer systems being utilized.

In yet another embodiment, the disclosed methods may be partially implemented in software that can be stored on a storage medium, executed on programmed general-purpose computer with the cooperation of a controller and memory, a special purpose computer, a microprocessor, or the like. In these instances, the systems and methods of this disclosure can be implemented as program embedded on personal computer such as an applet, JAVA® or CGI script, as a resource residing on a server or computer workstation, as a routine embedded in a dedicated measurement system, system component, or the like. The system can also be implemented by physically incorporating the system and/or method into a software and/or hardware system.

Although the present disclosure describes components and functions implemented in the aspects, embodiments, and/or configurations with reference to particular standards and protocols, the aspects, embodiments, and/or configurations are not limited to such standards and protocols. Other similar standards and protocols not mentioned herein are in existence and are considered to be included in the present disclosure. Moreover, the standards and protocols mentioned herein and other similar standards and protocols not mentioned herein are periodically superseded by faster or more effective equivalents having essentially the same functions. Such replacement standards and protocols having the same functions are considered equivalents included in the present disclosure.

The present disclosure, in various aspects, embodiments, and/or configurations, includes components, methods, processes, systems and/or apparatus substantially as depicted and described herein, including various aspects, embodiments, configurations embodiments, subcombinations, and/or subsets thereof. Those of skill in the art will understand how to make and use the disclosed aspects, embodiments, and/or configurations after understanding the present disclosure. The present disclosure, in various aspects, embodiments, and/or configurations, includes providing devices and processes in the absence of items not depicted and/or described herein or in various aspects, embodiments, and/or configurations hereof, including in the absence of such items as may have been used in previous devices or processes, e.g., for improving performance, achieving ease and\or reducing cost of implementation.

The foregoing discussion has been presented for purposes of illustration and description. The foregoing is not intended to limit the disclosure to the form or forms disclosed herein. In the foregoing Detailed Description for example, various features of the disclosure are grouped together in one or more aspects, embodiments, and/or configurations for the purpose of streamlining the disclosure. The features of the aspects, embodiments, and/or configurations of the disclosure may be combined in alternate aspects, embodiments, and/or configurations other than those discussed above. This method of disclosure is not to be interpreted as reflecting an intention that the claims require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed aspect, embodiment, and/or configuration. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate preferred embodiment of the disclosure.

Moreover, though the description has included description of one or more aspects, embodiments, and/or configurations and certain variations and modifications, other variations, combinations, and modifications are within the scope of the disclosure, e.g., as may be within the skill and knowledge of those in the art, after understanding the present disclosure. It is intended to obtain rights which include alternative aspects, embodiments, and/or configurations to the extent permitted, including alternate, interchangeable and/or equivalent structures, functions, ranges or steps to those claimed, whether or not such alternate, interchangeable and/or equivalent structures, functions, ranges or steps are disclosed herein, and without intending to publicly dedicate any patentable subject matter. 

What is claimed is:
 1. A system, comprising a laser catheter; an optical member configured to receive a laser beam along an optical path and rotate to a selected position to redirect, by optical refraction, the laser beam from the optical path onto one or more sets of optical fibers of the laser catheter, wherein a distal end of the laser catheter irradiates an endovascular structure; a detector configured to sense: at a first time, a first position of the optical member, wherein at the first position, the redirected laser beam irradiates a first, but not a second, set of optical fibers; and at a second time, a second position of the optical member, wherein at the second position, the redirected laser beam irradiates the second, but not the first, set of optical fibers, a microprocessor executable controller operable to select at least one set of optical fibers for optical channels comprising the one or more sets of optical fibers at least based on imaging information including a current location of a distal tip of the laser catheter; wherein the optical member comprises a pair of wedge prisms: wherein the pair of wedge prisms are configured as an anamorphic pair of optical members that enable steering by an independent rotation of each wedge prism of the laser beam in an area defined by a circle comprising a full angle 4θ wherein θ is a deviation from a single prism; and the system further includes: a locating member configured to rotate simultaneously and in amount related to rotation of each wedge prism of the pair of wedge prisms, wherein the detector is configured to determine a position of each rotating wedge prism by: emitting light onto the locating member; detecting a reflected spectra from the locating member; mapping the reflected spectra against a lookup table that indexes each absolute and/or relative position around the locating member against a corresponding set of reflected spectra; and based on the mapping, generating a locating signal to a motor to rotate at least one of the wedge prisms to a selected angle to redirect the laser beam with the optical member.
 2. The system of claim 1, wherein the microprocessor executable controller is further operable to select a number of optical channels, a configuration of fibers in an optical channel, an optical channel to be irradiated, and an ordering of optical channel irradiation based on at least one of a total fiber active area of the laser catheter, imaging information regarding a target endovascular structure, imaging information regarding: a non-target endovascular structure; a target endovascular structure characterization information; and an orientation of the distal tip of the laser catheter.
 3. The system of claim 1, wherein each rotating wedge prism is configured to redirect the laser beam such that the laser beam irradiates plural optical fibers positioned along an arc defined by the laser beam during rotation of the wedge prism.
 4. A system, comprising: a laser catheter; a microprocessor executable controller operable to select at least one of a fiber active area for each optical channel, a number of optical channels, a configuration of fibers in an optical channel, and an optical channel which is irradiated, based on at least a total fiber active area of the laser catheter and an orientation of the distal tip of the laser catheter; a pair of wedge prisms: wherein the pair of wedge prisms are configured as an anamorphic pair of optical members that enable steering of the laser beam by an independent rotation of each wedge prism in an area defined by a circle comprising a full angle 4θ wherein θ is a deviation from a single prism; a detector configured to sense: at a first time, a first position of a wedge prism, wherein at the first position, the redirected laser beam irradiates a first, but not a second, set of optical fibers, and at a second time, a second position of the wedge prism, wherein at the second position, the redirected laser beam irradiates the second, but not the first, set of optical fibers; and a locating member configured to rotate simultaneously and in amount related to rotation of each wedge prism of the pair of wedge prisms, wherein the detector is configured to determine a position of each rotating wedge prism by: emitting light onto the locating member; detecting a reflected spectra from the locating member; mapping the reflected spectra against a lookup table that indexes each absolute and/or relative position around the locating member against a corresponding set of reflected spectra; and based on the mapping, generating a locating signal to a motor to rotate at least one of the wedge prisms to a selected angle to redirect the laser beam with the optical member. 